Individual allow-list entries, e.g. a TOML array's elements.
'all' must be the sole entry; 'recommended' merges the curated
safe list at its position.
Parse an already-split shell allow-list.
Unlike parse_shell_allow_list, this takes separate elements so no comma
reparsing occurs — a command name containing a comma (valid on POSIX)
survives intact instead of being split into two entries.
